A 40-year-old man presented to our hospital because of a painless lump on his right forehead. Radiography showed a radiolucent defect in the frontal bone. Bone window computed tomography demonstrated a lucent mass which expanded externally from the diploë destroying and passing through the outer plate. T₁-weighted magnetic resonance imaging revealed the lesion as non-homogeneously isointense, and T₂-weighted imaging as non-homogeneously hyperintense. The lesion was enhanced non-homogeneously after contrast administration. The lesion was subtotally removed. Histological examination suggested cavernous hemangioma. Preoperative examinations could not provide a definitive diagnosis, which was established by the operative finding. Because of the difficulty of diagnosis in the early stage, surgical treatment in the early stage is recommended for total removal and definitive diagnosis of intraosseous tumor.